本文選題：生物結皮 + 藻類　； 參考：《北京林業(yè)大學》2015年博士論文

【摘要】：氮素養(yǎng)分的匱乏嚴重制約著荒漠生態(tài)系統的凈初級生產力。生物土壤結皮(下稱“生物結皮”)在荒漠生態(tài)系統廣泛分布,是主要的氮源。生物結皮因其土壤理化性質和生物群落結構的改變,強烈地影響著表層土壤氮素動態(tài),進而影響著表層土壤可利用氮素的供給,以及植被的生長和發(fā)育,對于荒漠生態(tài)系統土壤改良和植被恢復具有重要的實踐指導意義。目前,相關研究不夠系統和深入,一定程度上制約著對荒漠生態(tài)系統氮動態(tài)過程的理解以及荒漠化防治工作的開展。鑒于此,本研究以毛烏素沙地普遍存在的不同類型生物結皮為研究對象,進行了野外調查、室內模擬實驗、化學試驗和生物學實驗,對其物種群落結構、固氮能力、礦質氮積累和氮損失的等方面進行了研究,結果表明：(1)生物結皮的物種群落結構對固氮活性有著重要的貢獻。隨著生物結皮從低級到高級階段,固氮物種豐富度和多度與固氮活性呈現相同的變化趨勢,即單峰曲線。生物結皮的固氮物種,尤其是藍藻,對固氮活性具有顯著的的貢獻(90.9%)。并且藍藻對于固氮活性的貢獻又因水分和溫度條件不同而不同。水分和溫度條件越適宜,藍藻對于固氮活性的解釋量越高,在最適條件下(含水量25%,25℃),其解釋量高達96.9%。在不同類型的生物結皮當中,藍藻結皮的年固氮量估算值最高,為14.43±1.18mgN2m-2a-1。生物結皮中可能存在一些高多度且對溫度水分高敏感度的藍藻,它們只在溫度水分最適的環(huán)境條件下表現出高固氮活性。(2)隨著生物結皮從低級階段到高級階段,土壤物理結構得到改良和土壤養(yǎng)分不斷積累,微生物數量也大體上呈增加趨勢,這些都為土壤氮礦化作用提供了良好的條件,有利于提高土壤礦質氮含量。生物結皮礦質氮的積累與生物結皮的水分和溫度呈正相關；隨著土壤有機碳、全氮、有效氮含量和土壤體積分形維數的增加而增加,隨著土壤C/N和pH的降低而增加；與細菌、放線菌和真菌的數量呈正相關。在不同季節(jié)中,由于6-8月溫度水分條件較好,生物結皮碳氮養(yǎng)分含量較高,可以為氮礦化作用提供良好的條件和原料,因而該季節(jié)的礦質氮含量最高。(3)隨著生物結皮從低級階段到高級階段,土壤結構不斷改良,土壤透氣性不斷增加,堿性危害逐漸降低,進而有效地抑制了土壤氣體氮損失。生物結皮從低級階段到高級階段,土壤體積分析形維數和土壤孔隙度的增加抑制了氮損失,C/N和pH的下降減少了氮損失。本研究表明生物結皮對于荒漠生態(tài)系統表層土壤氮動態(tài)有顯著的影響,生物結皮的出現和發(fā)育總體上有利于土壤可利用氮的積累和氣體氮損失的減輕,為荒漠化防治工作中的生物措施提供了理論和實驗基礎。微生物和隱花植物是生物結皮實現氮動態(tài)過程的主要執(zhí)行者,其群落結構與固氮功能和礦質氮積累密切相關。后續(xù)研究可以采用新技術來檢測參與氮動態(tài)過程的功能微生物群落,以期闡明生物結皮氮素動態(tài)的生物機制。
[Abstract]:The lack of nitrogen seriously restricts the net primary productivity of desert ecosystem. The biological soil crust (hereinafter referred to as "biological crust") are widely distributed in the desert ecosystem, is the main source of nitrogen. The skin microbiotic soil physicochemical properties and biological community structure changes, strongly influence the dynamics of nitrogen in surface soil. And the effects of soil available nitrogen supply, and vegetation growth and development, are important for ecosystem restoration of desert vegetation and soil improvement. At present, the related research is not systematic and in-depth, to a certain extent restricts on desert ecosystem nitrogen dynamic process of understanding and carry out the prevention and control of desertification. In view of this, different types of biological crusts in Maowusu sandland generally exist in this study as the research object, conducted a field survey, indoor simulation experiment, test and biochemical studies Experimental study on the species, community structure, nitrogen fixation ability, mineral nitrogen accumulation and nitrogen loss were studied, results showed that: (1) species community structure of biological crusts are important contributors to the nitrogenase activity. With the biocrusts from elementary to advanced stage, species richness and nitrogen fixation and the nitrogenase activity showed the same trend, namely the single peak curve. The nitrogen fixing species of biological crusts, especially cyanobacteria, nitrogen fixation activity has significant contribution (90.9%). And the contribution to the nitrogenase activity of cyanobacteria due to moisture and temperature conditions are different. The more suitable conditions of moisture and temperature, the higher the cyanobacteria the nitrogenase activity explained, under the optimum conditions (25% water, 25 C), the amount of up to 96.9%. in the biological crusts of different types, in the amount of nitrogen fixing cyanobacterial crusts of the estimated value of the highest, 14.43 + 1.18mgN2m-2a-1. There may be some high degree of temperature and moisture sensitive cyanobacterial crusts, they are only in the most suitable temperature and moisture conditions showed high nitrogenase activity. (2) with biological crust from the lower stage to the higher stage, improved soil physical structure and soil nutrient accumulation, microbial number generally showed an increasing trend, provide a good condition for the soil nitrogen mineralization, is conducive to the improvement of mineral nitrogen content of soil moisture and temperature were positively biocrusts accumulation and biological crusts of mineral nitrogen related; with soil organic carbon, total nitrogen, available nitrogen content increased and the fractal dimension of soil volume increased and decreased with increasing soil C/N and pH; and the number of positive bacteria, actinomycetes and fungi. In different seasons, 6-8 months due to temperature and moisture conditions are better, higher biological carbon and nitrogen nutrient content of skin, Can provide good conditions and raw materials for nitrogen mineralization, and mineral nitrogen content of the season. The highest (3) with biological crust from the lower stage to the higher stage, improving soil structure, soil permeability increased, alkaline harm gradually reduced, thus effectively restrain soil nitrogen gas losses. Biocrusts from the lower stage to the higher stage, analysis of fractal dimension and porosity of soil can inhibit the nitrogen loss of soil volume, decreased C/N and pH reduced the nitrogen loss. This study shows that biological crusts have significant influence on soil nitrogen dynamics of desert ecosystem, biological crust and development to reduce the soil available the loss of nitrogen accumulation and nitrogen gas on the whole, provides theoretical and experimental basis for the prevention and control of desertification in microbial and biological measures. Cryptogamic crusts are nitrogen dynamic The main executors of the process are closely related to their community structure and nitrogen fixation function and mineral nitrogen accumulation. Subsequent research can use new technology to detect functional microbial communities involved in nitrogen dynamic process, with a view to elucidate the biological mechanism of nitrogen dynamics in biological crusts.

【學位授予單位】：北京林業(yè)大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：S154

【參考文獻】

相關期刊論文 前10條

1 周吉利;鄒剛華;彭佩欽;李勇;;中亞熱帶典型紅壤區(qū)土壤氮礦化動力學參數估算[J];農業(yè)現代化研究;2015年04期

2 虎瑞;王新平;潘顏霞;張亞峰;張浩;陳寧;;沙坡頭地區(qū)蘚類結皮土壤凈氮礦化作用的季節(jié)動態(tài)[J];應用生態(tài)學報;2015年04期

3 彭顯龍;劉洋;于彩蓮;王迪;;寒地稻田土壤氮素礦化特征的研究[J];中國農業(yè)科學;2014年04期

4 吉雪花;張元明;陶冶;周小兵;張靜;;蘚類結皮斑塊面積與環(huán)境因子的關系[J];中國沙漠;2013年06期

5 高廣磊;丁國棟;趙媛媛;馮薇;包巖峰;劉紫葳;;生物結皮發(fā)育對毛烏素沙地土壤粒度特征的影響[J];農業(yè)機械學報;2014年01期

6 婁煥杰;鄧煥廣;王東啟;陳振樓;李楊杰;;上海城市河岸帶土壤反硝化作用研究[J];環(huán)境科學學報;2013年04期

7 蘇郡;朱魯生;李絮花;王軍;謝慧;王金花;王琪;賈文濤;;氮磷肥料對HB-5菌株降解莠去津的促進作用及去毒效應的影響[J];環(huán)境科學;2010年10期

8 黨亞愛;李世清;王國棟;趙坤;;黃土高原典型土壤剖面土壤顆粒組成分形特征[J];農業(yè)工程學報;2009年09期

9 孫志高;劉景雙;;濕地土壤的硝化-反硝化作用及影響因素[J];土壤通報;2008年06期

10 黃曉星;于占源;錢偉;徐大勇;艾桂艷;;添加水對半干旱區(qū)沙質草地土壤氮有效性季節(jié)變化的影響(英文)[J];Journal of Forestry Research;2007年04期

相關博士學位論文 前1條

1 馮薇;毛烏素沙地生物結皮光合固碳過程及對土壤碳排放的影響[D];北京林業(yè)大學;2014年

，

本文編號：1738058